Possibility of enhancing algae drying by integrating infrasound

58 Pages·2017·1.22 MB·English

DEGREE PROJECT IN ENVIRONMENTAL ENGINEERING,
SECOND CYCLE, 30 CREDITS
STOCKHOLM, SWEDEN 2017
Possibility of enhancing algae
drying by integrating infrasound
YINGZI SANG
KTH ROYAL INSTITUTE OF TECHNOLOGY
SCHOOL OF ARCHITECTURE AND THE BUILT ENVIRONMENT
TRITA TRITA-IM-EX 2017:05
www.kth.se
Yingzi Sang
P
OSSIBILITY OF ENHANCING ALGAE DRYING BY

INTEGRATING INFRASOUND

Supervisor:
Mats Olsson
Fredrik Gröndahl
Johan Ahling

Examiner:
Fredrik Gröndahl

Master of Science Thesis
STOCKHOLM /YYYY/
PRESENTED AT
INDUSTRIAL ECOLOGY
ROYAL INSTITUTE OF TECHNOLOGY
TRITA-IM-EX 2017:05
Industrial Ecology,
Royal Institute of Technology
www.ima.kth.se
Abstract
With the aim of designing an infrasound-integrated technology which can enhance the
algae drying performance, this thesis provided the theoretical possibility of using
infrasound as an algae dehydration technology. To test the relation between algae drying
speed and other three parameters namely sound frequency, sound pressure and sample
mass, four major experimental groups including initial experiments and core
experiments with fifteen sub-experimental groups are designed. Results of the
experiments shows expected accordance with the theoretical inferences of infrasound
being an algae drying technology. Experiment steps and specifications are presented as
the research methodology. A real system with the drying capacity of 2 ton fresh algae
per day are designed based on the experimental calculations and results. Several
revisions including air circulation and infrasound resonance are made when scaling up
the research from experimental level up to industrial level. Other specifications of the
real system design follow the experiment results with regard of the research consistency.
Freeze drying technology is selected for the comparative cost analysis including
manufacturing costs and energy consumptions. Results shows infrasound-integrated
technology has a relatively low energy consumption whereas it costs more
manufacturing costs than freeze drying technology.
Research assumptions, limitations and recommendations for this research are described
in this article. From the author’s perspective, this paper can be used as an initiation and
instruction for larger scale researches in regard of infrasound-integrated algae
dehydration/drying.

Keywords: Algae storage and preservation; Infrasound; Drying method; Sustainable
technology

I
Acknowledgement

A lot of nice and kind people have offered great help in my thesis writing, including my
supervisors, my classmates and my parents.
Firstly, I would like to address my sincere gratitude towards Prof. Fredrik Gröndahl,
my supervisor at KTH who gave me the opportunity of starting this interesting topic
and offered me a large amount of relevant literatures. Without his efficient and clear
supervision, it is impossible for me to finish the thesis work within only 3 months.
My heartfelt thanks also go to Prof. Mats Olsson, the head of SVC and the sponsor for
the research budgets, for his great help in designing the experiments and real systems.
Without his great invention of infrasound generator, this thesis work would never start.
His patience and kindness guaranteed the quality of every remarkable supervisor
meeting.
I am also super pleased to acknowledge Johan Ahling, the owner of the Swedish Aero
Sport. He is the one who spent the most time with me during the experimental works.
He used his immense knowledge to help me solve the experimental errors. I would like
to say the Fika we had every time are the source of inspirational ideals for the research.
Besides, I am extremely grateful for my classmate Mengyin Hu, her comments and
wise advices were always useful in regard of errors revising and thesis refining.
Lastly, in particular, I would like to express my gratitude to my family for their constant
support. Every time when I felt tired and lost, their encouragement always acted as the
beacon light to help me go through the darkness.
Although the way to a more sustainable world is hard to walk, beauties do exist.
The nights during the long Nordic winter seem to be endless, I do have Joy.

II
Table of contents

Abstract ................................................................................................................................. I
Acknowledgement ............................................................................................................... II
Table of contents ................................................................................................................. III
List of figures ....................................................................................................................... V
List of tables ....................................................................................................................... VI
1. Introduction ....................................................................................................................... 1
1.1 Aims and objectives ..................................................................................................... 1
1.2 Algae as a promising bio-resource ............................................................................... 1
1.2.1 Algae as renewable energy .................................................................................... 1
1.2.2 Algae as solution towards CO mitigation ............................................................. 2
2
1.2.3 Other applications ................................................................................................. 2
1.3 Necessity of algae drying and its limitations ................................................................ 2
1.4 Infrasound as an emerging solution .............................................................................. 3
2. Methodology ............................................................................................................. 5
2.1 Particle displacement and sound frequency .................................................................. 5
2.2 Boundary layer theory ................................................................................................. 7
2.3 Drying system and its specifications ............................................................................ 8
2.3.1 Drying sections ..................................................................................................... 9
2.3.2 Sound box ........................................................................................................... 10
2.3.3 Infrasound generator ........................................................................................... 11
2.3.4 Hot air flow generator ......................................................................................... 11
2.3.5 Supplementary section ........................................................................................ 12
2.3.6 Measurement section .......................................................................................... 13
2.4 Initial experiments design .......................................................................................... 14
2.4.1 Experiment 1: Algae sample water content testing ............................................... 14
2.4.2 Experiment 2: Test the algae drying speed without infrasound ............................. 15
2.4.3 Experiment 3: Test the algae drying speed with 16 Hz infrasound ....................... 16
2.5 Core experiments setup .............................................................................................. 17
2.5.1 Algae drying with different sound frequencies ..................................................... 17
2.5.2 Algae drying with different sound pressures ........................................................ 19
2.6 Cost Analysis ............................................................................................................. 20
2.7 New system design .................................................................................................... 20
3. Results ............................................................................................................................ 21
3.1 Initial experiment ..................................................................................................... 21
3.1.1 Algae sample water content testing ..................................................................... 21
3.1.2 Testing the algae drying speed without infrasound .............................................. 22
3.1.3 Testing the algae drying speed with infrasound ................................................... 24
3.2 Core experiments ....................................................................................................... 26
3.2.1 Testing with different frequency (from 13 Hz to 19 Hz), 42.7 g sample mass ...... 27
III
3.2.2 Testing with different frequency (from 13 Hz to 19 Hz), 21.3 g sample mass ...... 28
3.2.3 Test using different sound pressure, 42.7 g sample mass ...................................... 30
3.2.4 Test using different sound pressure, 21.3 g sample mass .................................... 31
3.3 New system design .................................................................................................... 32
3.3.1 System boundary ................................................................................................ 32
3.3.2 Sketch of the real system ..................................................................................... 32
3.4 Cost and analysis ....................................................................................................... 33
3.4.1 Manufacturing costs System boundary ................................................................ 33
3.4.2 Energy consumption ........................................................................................... 34
4. Discussion ....................................................................................................................... 34
4.1 Initial experiments ..................................................................................................... 34
4.2 Infrasound as a solution ............................................................................................. 35
4.2.1 Discussion about the initial experiments .............................................................. 35
4.2.2 Sound frequency as an impact factor ................................................................... 37
4.2.3 Sample mass as an impact factor ......................................................................... 40
4.2.4 Sound pressure as an impact factor ...................................................................... 41
4.3 Other potential impact factors .................................................................................... 42
4.4 New system design for the Seafarm project ................................................................ 42
4.5 Cost analysis ............................................................................................................. 43
4.5.1 Energy consumption ........................................................................................... 43
4.5.2 Manufacturing cost ............................................................................................. 43
4.6 Assumptions and research limitations......................................................................... 44
5. Conclusions ..................................................................................................................... 44
6. References....................................................................................................................... 46

IV
List of figures
Figure 1.1 Laminar flue gas model in soot cleaning
Figure.1.2 Turbulent flue gas model in soot cleaning
Figure 2.1 Algae dehydration model and water boundary layer
Figure 2.2 Formation of the water boundary layer
Figure 2.3 Overall picture of the drying system
Figure 2.4 Drying tube
Figure 2.5 Drying cage
Figure 2.6 Sound box
Figure 2.7 Infrasound generator
Figure 2.8 Hot air flow generator
Figure 2.9 Amplifier
Figure 2.10 Function generator
Figure 2.11 Electronic thermometer
Figure 2.12 Countdown timer
Figure 2.13 Electronic scale
Figure 3.1 Relation between sample weight and time in the water content testing
Figure 3.2 Relation between sample mass and time in the test without infrasound
Figure 3.3 Relation between drying speed and time in the test without infrasound
Figure 3.4 Relation between relative water content and time in the test without infrasound
Figure 3.5 Relation between sample mass and time in the test with 16 Hz infrasound
Figure 3.6 Relation between drying speed and time in the test with 16 Hz infrasound
Figure 3.7 Relation between sample mass and time in the test with 16 Hz infrasound
Figure 3.8 Relative water content of each measurement interval at seven frequencies in the
42.7 g test
Figure 3.9 Relative water content of each measurement interval at seven frequencies in the
21.3 g test
Figure 3.10 Drying system boundary
Figure 3.11 Sketch of the new system design
Figure 3.12 Energy consumption of infrasound technology and freeze drying technology
Figure 4.1 Relation between sample weight and time in drying with 16 Hz/without infrasound
Figure 4.2 Average drying speed of drying with 16 Hz and without infrasound
Figure 4.3 Relation between relative water content and time in the initial experiments
Figure 4.4 Zoomed-up figure 3.8 at the time of 50 minutes
Figure 4.5 Average drying speed in different sample mass groups
Figure 4.6 Average drying speed in the tests of different sound pressures
Figure 4.7 Calculation of the drying speed in the 21.3 g test with 13 Hz sound frequency

V
List of tables

Table 2.1 Specifications of the water content testing
Table 2.2 Specifications of the drying test without infrasound
Table 2.3 Specifications of the drying test with infrasound
Table 2.4 Specifications of the 42.7g drying test with different sound frequencies
Table 2.5 Specifications of the 21.3g drying test with different sound frequencies
Table 2.6 Specifications of the 42.7g drying test with different sound pressures
Table 2.7 Specifications of the 21.3 g drying test with different sound pressures
Table 2.8 Nine sections of the drying system
Table 3.1 Sample weight and time in algae water content testing
Table 3.2 Relation between three parameters and time in drying tests without infrasound
Table 3.3 Relation between three parameters and time in drying tests with 16 Hz infrasound
Table 3.4 Relation between sound frequency and particle displacement
Table 3.5 Relation between sample mass (g) and time in the 42.7 g test at seven frequencies
Table 3.6 Average drying speed for seven frequencies in the 42.7 g test
Table 3.7 Relation between relative water content and time in the 42.7 g test at seven
frequencies
Table 3.8 Relation between sample mass (g) and time in the 21.3 g test at seven frequencies
Table 3.9 Average drying speed for seven frequencies in the 21.3 g test
Table 3.10 Relation between relative water content and time in the 21.3 g test at seven
frequencies
Table 3.11 Relation between sample mass and time at three sound pressures in 42.7 g test
Table 3.12 Average drying speed at three sound pressures in 42.7 g test
Table 3.13 Relation between sample mass and time at three sound pressures in 21.3 g test
Table 3.14 Average drying speed at three sound pressures in 42.7 g test
Table 3.15 specifications of the new system
Table 3.16 Manufacturing costs of the new system

VI